The invention relates to a resistor composition which comprises oxide, containing copper and ruthenium, and glass frit and the use thereof.
U.S. Pat. No. 3,896,055, which is hereby incorporated by reference, describes electrical resistor compositions containing as an electrically conductive phase polynary oxides having a pyrochlore related crystal structure of the general formula M.sub.x M'.sub.2-x M".sub.2 O.sub.7-z where M is silver and/or copper, M' is bismuth or a mixture of at least 1/2 bismuth plus up to 1/2 cadmium, lead, yttrium, thallium, indium and/or rare earth metal and M" is ruthenium, iridium and/or a mixture of at least 3/4 ruthenium and/or iridium and up to 1/4 platinum and/or titanium and/or rhodium. In an amount of 5-90%, they form, together with glass frits or other suitable inorganic binding agents, the solid substance portion of the resistor compositions. In order to be printable, these compositions must contain a liquid organic carrier, for example a solution of ethyl cellulose in terpineol. Resistors of a particularly low specific resistance and a flat response of the specific resistance to temperature can be produced by firing the resistor compositions onto dielectric substrates, for example aluminum oxide, at approximately 650.degree.-950.degree. C.
U.S. Pat. No. 4,420,422 concerns a method of preparing pyrochlore compounds of the general formula Bi.sub.2-x M.sub.x B.sub.2 O.sub.7-z where M=cadmium, copper, lead, indium, gadolinium and/or silver and B=ruthenium and/or iridium all of which have a high surface area and are suitable for resistors with relatively low values for the temperature coefficient of resistance in a range between +25.degree. C. and +125.degree. C.
Resistor compositions which contain oxides of the general formula M.sub.x M'.sub.y (Pb, Bi).sub.2-x-y Ru.sub.2 O.sub.7-z where M=copper and/or silver, M'=calcium, strontium, and/or barium are known from German application P 39 14 844.0. The resistor films made from these resistor compositions are distinguished by a low temperature coefficient of resistance and only a small difference between the temperature coefficient of resistance in the range of 25.degree. C. to +125.degree. C. and the temperature coefficient of resistance in the range of -55.degree. C. to +25.degree. C.